My first instinct was that this is, at the very least, not common in classical Latin, and should only happen with participles that are basically adjectives and have lost some of their verbal semantics, like sapiens or patiens. The reason I think that, is that a present participle is perfectly capable of standing on its own in Latin, it doesn't need an actual conjugated form to accompany it and signal its verbal status.
Anyway, I'm a corpus guy, and I'd love to be able to just query for this kind of thing. But since I'm not exactly there yet with my scanning engine, I have looked for nominative participles + esse in raw data by just going over part of my verse corpus manually for a minute or two.
The first two results seem to corroborate my intuitive hypothesis (which are fancy words for "hunch"). The last ones, if properly read, seem to be examples of what you're looking for. So yes, it does occur sporadically, but the question remains how much of the verbal meaning is left over. Are these adjectivized verbs, or adjectives derived from verbs ?
nostra nocens anima est. ego te, miseranda, peremi, (Ov. Met. IV, 110)
verticibusque frequens erat atque inpervius amnis. (Ov. Met. IX, 106)
non poteram, longi patiens erat ille laboris. (Ov. Met. V, 611)
conveniens Venus est annis temeraria nostris. (Ov. Met. IX, 553)